Method and apparatus for melt-spinning and cooling a plurality of filaments

Abstract

A method and an apparatus for melt-spinning and cooling a plurality of filaments which are processed to form a non-woven fabric or web. The filaments are guided after extrusion in the form of a filament curtain through a cooling zone and are cooled by a cooling air stream blown transversely to the filament curtain. In order to prevent the flow effects created by air swirls in the side edge zones of the filament curtain, an additional quenching air stream acts inside the cooling zone on each side edge of the filament curtain. For this purpose, the inventive apparatus comprises a quenching member positioned below each longitudinal end of the spinneret.

Description

BACKGROUND OF THE INVENTION [0001] The present invention relates to a method for melt spinning and cooling a plurality of filaments used in the production of a non-woven fabric or web, and also an apparatus for carrying out the method. [0002] It is known when manufacturing spun-bonded fabric that a plurality of filaments are extruded in a spinning apparatus, cooled collectively as a filament curtain and are deposited to form a non-woven fabric. For this purpose, draw-off nozzles are used, which draw off the filament curtain from the spinning apparatus and guide it to a delivery belt arranged below the draw-off nozzle. For cooling the freshly extruded filaments, the filaments are quenched with a cooling air stream which moves transversely to the filament curtain, so that the filaments are strengthened before entering into the draw-off nozzle. Such a method and / or apparatus are known, e.g., from U.S. Pat. No. 6,183,684. [0003] In order to be able to meet the requirements of uniformity...

AI Technical Summary

Benefits of technology

[0006] The above and other objects and advantages of the invention are achieved by a method and apparatus of the above described type and wherein the filaments guided in the side edge zones of the filament curtain are guided in a predetermined atmosphere using defined flow ratios. For this purpose an additional quenching air stream created at least at the front end of the spinneret by a quenching member acts directly on the filaments at the side edge of the filament curtain. Air swirls caused by a transversely directed cooling air stream on the side edge of the filament curtain can thus be prevented advantageously. A balancing of the quenching ratios, in particular, can be achieved using the quenching air stream.

[0008] In order to bring about the cooling of the filaments of the filament curtain essentially using the transversely oriented cooling air stream, the improved configuration of the inventive method is particularly advantageous in which the quenching air stream is generated next to the side edge of the filament curtain in a quenching direction that has a component oriented in the running direction of the filaments, and wherein a quenching angle in the range of 0° to 45° is provided between the filaments and the quenching stream. Thus in the extreme case, a parallel flow relative to the filament curtain can be provided, wherein said parallel flow essentially influences only the side edge air layers of the filament curtain. In order to be able to use additional cooling effects of the quenching air stream, the quenching angle is advantageously increased, wherein quenching angles in the range of up to 45° have turned out to be suitable for the purpose of preventing any unreliable differences between the cooling conditions in the center of the filament curtain and those at the side edges of the filament curtain.

[0011] In order to achieve the most effectual impact over the entire cooling length in the side edges of the filament curtain, the quenching air stream is created according to an advantageous variant of the method at a quenching speed, which is greater than that of the cooling air stream. It is thus possible to create a turbulence free flow in the border region of the filament curtain up to the outlet of the cooling unit.

[0015] The inventive apparatus is operated according to a preferred improved configuration using a cooling unit, which contains a cooling wall with a cooling chamber, on both longitudinal sides of the spinneret. Two separate cooling air streams can thus be created, each of which is oriented towards the filaments transversely to the filament curtain. Such cooling units enable an intensive cooling, as a result of which high process speeds are possible even in case of high filament densities inside the filament curtain.

Problems solved by technology

However, this helps achieve only certain flow guidances of the cooling air in relation to the atmosphere.

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